


Literal Chemistry

by bummy_bum



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alternate Universe - College/University, Getting Together, Inexperienced Ishigami Senkuu, M/M, Smut
Language: English
Status: Completed
Published: 2020-04-16
Updated: 2020-04-16
Packaged: 2021-03-02 01:53:36
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,485
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23687221
Author URL: https://archiveofourown.org/users/bummy_bum/pseuds/bummy_bum
Summary: “Wow Senkuu-chan, I’m surprised. You didn’t like her? Wasn’t she cute?” Gen pestered.“I don’t like girls,” Senkuu bluntly answered.“Do you like boys?”“...” Senkuu didn’t respond, but a slight blush appeared on his cheeks.
Relationships: Asagiri Gen/Ishigami Senkuu
Comments: 6
Kudos: 114





	Literal Chemistry

**Author's Note:**

> the college au no one asked for but everyone needed lol

“Excuse me...uh...do you know where the paraformaldehyde is?” Senkuu asked his Chemistry lab’s graduate teaching assistant, Asagiri Gen.

_ Wow...when will he learn my name? Gen _ thought to himself as he forced a smile. “Parafor...what?”

“Paraformaldehyde.”

“Oh!” Gen walked over to the laboratory’s refrigerator and grabbed the bottle labeled ‘paraformaldehyde’. “Here you go, Senkuu-chan.”

“Thanks—“

“It’s Gen,” Gen chimed in.

“Thanks...Gen,” Senkuu said as he proceeded to return to his bench and continued to work alone. Everyone in the lab had a partner, except for Senkuu since there was an uneven amount of students and the professor trusted him enough to handle the workload on his own.

Everyday, Gen would watch Senkuu in amazement—always quickly finishing the protocols and sticking around simply to work on his own approved projects. Gen only wanted this teaching assistant position to slap it on his resume. He barely even got an A in the class when he took it, and was never much of a chemist.

Gen hovered around the class, hoping for Senkuu to ask him a question. Although Senkuu rarely needed help, Gen couldn’t help wanting to talk to him. The way Senkuu’s eyes looked as he worked on his experiments never failed to make Gen’s heart flutter, he thought it was cute. Senkuu’s acknowledgement was all he wanted, or at least for him to remember his name...

The lab session was coming to an end, and Senkuu hadn’t spoken to Gen since earlier which made him momentarily disappointed. However, he stayed optimistic.  _ We’ll talk more next time... _

“Have a good night...Asagiri Gen.” Senkuu’s voice startled Gen, but by the time he turned to respond, Senkuu had already gone.

* * *

Two days later, Senkuu showed up to the open lab (as he always does) that Gen was supervising. Most days, it would just be Senkuu and the teaching assistant, and the open labs Gen was in charge of weren’t any different. It would just be the two of them and Gen would always ask what kinds of projects Senkuu was working on. Although he didn’t quite understand everything Senkuu said, he admired how passionate Senkuu was about science. He felt envious of him, who cared so much about something since he’d never felt that strongly about anything.

“Hi Gen,” Senkuu said as he walked over to the lab bench.

Gen blushed. Hearing his name come out of Senkuu’s mouth made him feel slightly discomposed. “Hello Senkuu-chan!” Gen responded, following Senkuu to his lab bench. “What are you going to work on today?”

A shimmer appeared in Senkuu’s eyes. “I’m studying the properties of the element  Flerovium by...”

Gen tried to maintain his attention, but was often distracted by his fixation on Senkuu — the excitement in his voice; the passion in his eyes; his sender wrist...his soft lips... _ FOCUS GEN! _

“...so I should be done by next week,” Senkuu finished.

“Wow, that’s amazing Senkuu-chan.” Gen tried to seem as though he comprehended everything he said, but based on the  perspicacious expression Senkuu was making, it didn’t seem to be very convincing. Even though he could tell that Gen was simply entertaining him, he enjoyed having someone that showed interest in him. “Can I ask you something, Senkuu-chan?”

Before Senkuu could even respond, they were interrupted by another student entering the lab.

“Hi Asagiri!” The female student exclaimed. “Can you help me with this? I have to redo a part of the experiment from last class.”

“We’ll finish this later,” Gen said while placing his hand on top of Senkuu’s, giving it a light squeeze before walking over to the other student. 

Although visibly flustered, Senkuu continued to work on his experiment; curiously looking over to Gen and his classmate ever so often.  _ I wonder what he was going to ask me... _

“Asagiri...I don’t think this is right...” Senkuu overheard the female student say. He instinctively stood up, feeling the need to go over to help.

Senkuu was immediately able to figure out the problem. It was a simple conversion error.

“Thank you, Ishigami!” The girl exclaimed. “You’re so smart.” She touched Senkuu’s upper arm, but he quickly jerked it away, unable to hide the look of disgust off his face. 

“Well, I’ll be going then.” The girl picked up all of her things and hastily exited the laboratory.

“Wow Senkuu-chan, I’m surprised. You didn’t like her? Wasn’t she cute?” Gen pestered.

“I don’t like girls,” Senkuu bluntly answered.

“Do you like boys?”

“...” Senkuu didn’t respond, but a slight blush appeared on his cheeks.

Gen could tell that this was something Senkuu hadn’t really thought about before. He took a couple of steps closer to him, placing Senkuu in between him and the lab bench. “Or do you just like science?”

“No...It’s not—” But before Senkuu could fully respond, Gen leaned forward and kissed him. Senkuu’s eyes widened at the shock of feeling someone else’s mouth on his own. It was his first kiss. 

Gen could sense that Senkuu was feeling uncomfortable, but since he didn’t push him away, Gen decided to keep going. “Relax...” He whispered across Senkuu’s lips before returning to the kiss. He felt Senkuu become less tense and saw it as an invitation to continue. His tongue traced across Senkuu’s lips until he felt them slightly part. While gripping onto the back of Senkuu’s neck, he deepened the kiss, pushing his tongue into Senkuu’s mouth.

These unfamiliar sensations confused Senkuu. His body had never reacted this way before; it was a completely new feeling. Senkuu let out a soft moan as Gen massaged their tongue’s together. He didn’t know why, but kissing Gen felt so good... _ Am I attracted to Gen?! _

Senkuu felt something at the bottom of his shirt. Shortly after, Gen’s fingers were running lightly over his abdomen to which he became so flustered that he pushed Gen away. His body became tense again and for the first time, he got an erection.

They stood inches apart from each other, both catching their breaths and completely flushed. “Uhhh...I should get going.” Senkuu rushed to get his things and quickly exited the lab.

Gen sat down, absolutely bewildered by what had just happened—all he knew was that he wanted to do it again.

* * *

_ Gen and I kissed...I let Gen kiss me...Gen KISSED me...?  _ Senkuu’s thoughts were completely jumbled. He tried to think of a practical reason for his feelings, but nothing made sense. He couldn’t understand why he didn’t feel nauseous when Gen touched him or how he didn’t want to immediately push Gen away when he came near. It was as though he actually  _ liked _ the things he and Gen did...but why?

Senkuu had never been someone to have crushes and he never thought about stuff like kissing or touching or.... _ other things.  _ His mind began to drift to activities he never would have normally thought himself to partake in. Just his imagination alone was enough to make him hard again.

Everything he was experiencing made him certain that he was indeed attracted to Gen. However, Senkuu wanted a reason...he needed a reason and in order to get accurate results, what he needed was more data.

* * *

It had been a couple days since Gen and Senkuu’s kiss—although neither of them spent too long not thinking about it.

Once again, it was another open lab. Gen walked into the laboratory a little late, not surprised to see that Senkuu was already there. He briefly felt Senkuu’s eyes on him, but noticed that he quickly looked away, pretending as though he hadn’t looked at him at all.

“Hi Senkuu-chan.”

Senkuu could feel his heart beating. “...Hi Gen.” 

There was an awkward tension between them. Gen wanted to talk to Senkuu about what happened, but a couple of other students actually showed up to the open lab and occupied most of Gen’s time. Even though he was helping the other students, Gen often glanced over to Senkuu and would occasionally catch him looking over at him, which he found to be irresistibly cute.

“Thank you, Asagiri!”

“Thanks, Asagiri Gen. Have a good night.” 

The two other students left, leaving Gen and Senkuu alone. They sat in silence as Senkuu continued working on his experiments. Eventually, Gen decided to make his way over to Senkuu’s lab bench. 

Senkuu finally decided to break the silence. “Gen...”

“Yes, Senkuu-chan?”

“Can we...do  _ that  _ again?” Senkuu guardedly asked. 

Gen noticed Senkuu’s cheeks begin to blossom. It made him smile. “Do what?” He teased.

“...Uhh...nevermind...” Senkuu’s face completely reddened, then he diligently returned to working on his experiment, just to be interrupted by a kiss from Gen.

“You mean this?” He smiled as he pulled away from Senkuu. 

Senkuu grabbed onto Gen’s tie that dangled in front of him, and pulled him back into the kiss. Senkuu kept his eyes open and his lips shut. He simultaneously made notes in his mind about anything he thought to be viable data as to why he was attracted to Asagiri Gen.

Gen chuckled against Senkuu’s closed mouth. “Senkuu-chan, you really need to learn to relax,” he laughed as he brushed his fingers through Senkuu’s hair. “Sit here.” Gen started to push all the contents on the lab bench to the side, but Senkuu stopped him.

“Don’t push the microscope!” Senkuu exclaimed, grabbing onto Gen’s arm. “Sorry...I didn't mean to yell, but I have some important slides on there. Let me put it away real quick.”

Gen couldn’t help but laugh. “I’m not laughing at you Senkuu-chan...you’re just really cute.”

Senkuu had no idea how to respond to that.  _ Cute? No one has ever called me cute before... _

He returned and sat on the lab bench. Gen stood in between Senkuu’s legs. “Close your eyes.”

Senkuu didn’t quite understand why he should close his eyes while kissing, but he did it anyway. He felt Gen bring his lips to his once again. It suddenly clicked in his mind why he should close his eyes, since now he was able to feel the kiss even more than before—Gen’s lips were soft and warm; Senkuu felt as though he were melting into them. 

“You can wrap your arms around my neck, Senkuu-chan,” Gen whispered before returning to Senkuu’s lips. Gen ran the tip of his tongue over the outline of Senkuu’s lips and Senkuu separated them, allowing Gen to explore inside his mouth. 

Their teeth clicked as the kiss became more intense. Senkuu moved one of his hands down to Gen’s chest, letting him feel his rapid heartbeat. He added another data point for further analysis. Increase in heart rate.  _ Why are our bodies reacting this way? _

Feeling Gen’s heart beat made Senkuu’s chest feel tight.  _ Why? _ Not only did his chest tense...he could feel his cock pushing against his pants. He wondered if Gen was the same.

Gen’s hands gripped onto Senkuu’s waist, causing him to wince a bit. “Your body is so sensitive, Senkuu-chan,” Gen spoke onto Senkuu’s lips before moving his head down and lightly biting Senkuu’s collarbone.

“Mmmm...” Senkuu groaned.

One of Gen’s hands made its way to Senkuu’s crotch, where he felt his erect cock. “Senkuu-chan you’re hard...me too.” Gen grabbed Senkuu’s hand and moved it down to his crotch, letting him feel his erection as well.

This was the first time Senkuu had felt another man’s cock. It pushed against his hand, causing his own cock to twitch in excitement. At that moment, Senkuu was speechless. 

“Are you a virgin, Senkuu-chan?”

“...Yes.”

Gen wasn’t too surprised by this confirmation. He smirked. “You must’ve at least touched yourself before, right?”

“...No, I’ve never...”

“WHAT?!” Gen was shocked, he had suspected that Senkuu was a virgin...but to have never even masturbated? It just seemed absurd. 

Gen walked over to the lab entrance and made sure that the door was securely closed. “Well, I’ll teach you.”

He walked back to Senkuu, placing his hand back onto Senkuu’s cock. “Wait! Gen, what if someone walks in?”

“Don’t worry, Senkuu-chan. No one comes in here this late. And not that many people have access anyways.” Gen reassured him.

He tugged on Senkuu’s pants, completely pulling them off, revealing Senkuu’s erect cock. 

Senkuu felt embarrassed by how exposed he was, and the way Gen was staring at his cock didn’t help.

Gen sat in a nearby chair, positioning himself in between Senkuu’s legs. He gripped onto Senkuu’s thighs, slightly kneading his fingers into his skin. Bringing his face to Senkuu’s inner thighs, he started sucking on various parts of his skin, increasingly getting closer to Senkuu’s cock.

Gen took one of his hands and wrapped his fingers around Senkuu’s cock causing him to let out a muffled moan. He gently began to move his hand up and down and rubbed his thumb on the tip before taking it into his mouth. 

“Ahh...Gen stop...”   


Gen lifted his head, “What’s wrong?”

“Nothing...” Senkuu didn’t actually know why he told Gen to stop. Gen lip’s around his cock felt incredible.

“Do you want me to stop?”

“No, don’t stop,” Senkuu quickly responded, sounding a bit more desperate than intended. “I mean, you can keep going...” 

Gen smiled before taking Senkuu’s cock back into his mouth, bobbing his head up and down at a slow place, taking in the entire length every time. He used his tongue to massage the tip, tasting the bit of pre-cum that came out. Senkuu’s cock began to twitch inside Gen’s mouth, making Gen believe that Senkuu was going to climax soon. So, he lifted his head, letting Senkuu’s cock fall from his mouth.

Senkuu’s hand cupped Gen’s face and he leaned in to kiss him. “Let me return the favor...” Senkuu broke away from the kiss and got off the lab bench, dropping to his knees right in front of Gen. He started unbuckling his pants, before completely removing them. 

“Exhilarating...” Senkuu accidentally spoke out loud, causing Gen to chuckle.

“You really are cute, Senkuu-chan.”

Senkuu’s face became completely flushed and he decided to take the entire length of Gen’s cock into his mouth, until it hit the back of his throat. Gen let out a lengthy moan and his body began to quiver, but Senkuu had underestimated the repercussions of his actions. His reflexes kicked in, and the contact between Gen’s cock and his uvula caused him to gag. Senkuu lifted his head and started to cough.

“Are you okay?” Gen grabbed onto Senkuu’s shoulders in concern.

“I’m okay,” Senkuu reassured him.

“You don’t have to push yourself like that...even though it did feel really good,” Gen purred.

“Should I keep going?”

There was a somewhat mischievous look on Gen’s face. “Actually...can I fuck you Senkuu-chan?” 

Gen’s straightforwardness surprised Senkuu, but even though he had never had sex before he responded, “Yes.” 

Their lips met again. Gen helped Senkuu stand up and led him to the lab bench. He bent him over and reached for a tube that was next to Senkuu.

“Sorry, I don’t have any lube, so I’m going to just use some glass lubricant instead.”

“It’s okay,” Senkuu responded, feeling completely embarrassed in the position he was in. 

Gen squeezed some of the lube onto his finger and started to rub it on Senkuu’s entrance causing his hole to tense a bit. He started poking his finger in, gradually increasing how deep he went until his entire finger was inside. Slightly bending his finger, he continued fingering Senkuu’s ass. 

“Nghh...” Senkuu quietly moaned. He never thought he could feel this much pleasure by having a finger up his ass.

Although he didn’t say it out loud, Gen wanted to hear all of Senkuu’s erotic noises. So far, Senkuu had muffled all his moans—Gen set a goal for himself: make Senkuu moan as loud as he can. 

Gen added another finger, and spread them apart as he entered Senkuu’s hole. He continued to finger Senkuu, trying to loosen his hole as much as he could—eventually reaching three fingers. A slight whimpering noise exited Senkuu’s mouth.

“You don’t have to hold back Senkuu-chan.” Gen rested his body on Senkuu’s back and whispered, “I want to hear all your sexy noises...”

After Gen thought that he loosened Senkuu enough, he removed his fingers and used the same hand to grab his own cock, giving it a few pumps before rubbing the head against Senkuu’s entrance.

The touch of Gen’s cock on his ass caused Senkuu to start mentally preparing himself for what was about to happen.

“I’m going to put it in now,” Gen announced as he pushed the tip of his cock into Senkuu’s entrance.

“Ahh—“ Senkuu moaned a little louder than before, but covered his hand with his mouth as Gen slowly pushed his cock into him. It felt really weird and unnatural, but pleasurable at the same time. For some reason, Senkuu liked the feeling of Gen’s cock inside him.

“Is it okay if I move?”

“Yeah...”

Gen began slowly thrusting in and out of Senkuu. “Nghh...you’re so tight, Senkuu-chan...ahhh”

With each stroke, Senkuu felt Gen go deeper. The feeling of Gen’s cock entering him was nothing Senkuu expected it to be, it felt ten billion times better. “Ahhhh!” Senkuu cried out as Gen increased his pace and hit a spot that Senkuu figured to be his prostate. 

“I finally got Senkuu-chan to moan.” Gen smirked as he once again thrusted into Senkuu causing him to let out another moan of similar caliber. 

Gen looked down and watched as his cock entered Senkuu’s ass. “This is so hot...you’re so sexy Senkuu-chan.”

Senkuu didn’t respond—he couldn’t respond, instead only continuous moans flooded from his mouth, filling the lab. Senkuu felt his own cock begin to throb, wanting to so desperately be touched. His hand began to travel down to his crotch but he was stopped by Gen.

“I’ll touch you Senkuu-chan,” Gen insisted as he wrapped his fingers around Senkuu’s cock and started jerking him off.

“Nghh...ahhh...Gen I-I think...ahhhh....” Before Senkuu could even finish speaking, he came all over the lab bench. Senkuu’s knees quivered as Gen continued to slowly stroke his cock, allowing him to ride out his orgasm.

“I’m about to come too...” Gen panted, gripping onto Senkuu’s hip and thrusting into him. He quickened his pace, slamming his hips against Senkuu’s ass. “Haahhh...” He moaned.

Gen felt himself nearing his orgasm, but something felt off. “Senkuu-chan, I want to see your face.”

Senkuu blushed at his words.  _ He wants to see my face... _ He thought to himself. However, another thought crossed his mind... _ I’m going to see Gen’s face when he comes. _

Senkuu turned around and laid back on the lab bench. Gen placed Senkuu’s legs over his shoulders, pushing his cock back inside Senkuu’s ass. 

Now that Senkuu could see Gen face-to-face, he felt himself heating up even more. The feeling of Gen thrusting into him was completely different than before. “Hahhh!” Senkuu cried out as Gen rapidly pounded into Senkuu. His cock became erect once again. “Gen...nghhh...I-I’m...ahhh...I’m going to come again...”

“Me too...Let’s come together.” Gen pulled out then held Senkuu’s and his cocks together, rubbing them as fast as he could. 

Gen couldn’t take his eyes off of Senkuu’s face, he made expressions Gen didn’t even know Senkuu could make. “Nghhhh...you’re so pretty Senkuu-chan...ahhhh!” Gen came into his hand. The cum dripped down his fingers and onto Senkuu’s cock. Senkuu liked how warm it felt against his sensitive cock.

“Nghhh...ahhh...” Senkuu felt the urge to come again. His cock throbbed in Gen’s hand. “Ahhhh!” Senkuu came again, some landing onto Gen’s face.

“Oh my god! I’m so sorry!” Senkuu apologized as he sat up in order to wipe his cum off of Gen’s face.

“It’s okay!” Gen reassured Senkuu, grabbing his hand. He pressed his lips against Senkuu’s and kissed him passionately. Senkuu opened his mouth inviting Gen to slip his tongue inside. 

* * *

After a couple of moments of rest, the two cleaned themselves up and started putting their clothes back on. 

“Would you want to do this again, Senkuu-chan?” 

“Yes...ten billion percent.” Senkuu smiled. He was completely certain that he wanted to keep seeing Gen. Although he couldn’t come to a conclusion at the time, he wanted to collect more data in order to produce some kind of answer as to why he feels the way he does. “Want to get some ramen?”

Gen blushed, “Are you asking me on a DATE?”

“No...that’s gross,” Senkuu rebutted, walking towards the exit. “Do you want to go or not?” He teased.

“I was joking, of course I want to go, Senkuu-chan!” Gen whined as he caught up to Senkuu and grabbed his wrist as they both left to go on their ‘not-a-date’.

**Author's Note:**

> senkuu did know gen’s name but he was being a shy boy 
> 
> also for anyone who has ever taken a chemistry lab, i know microscopes are barely used in chemistry labs...i wrote this during my biology lab and just felt like a chemistry lab setting fit better lmao ¯\\_(ツ)_/¯


End file.
